Hinge mechanism



Sept. 17, 1963 H. JQTENNISWOOD EI'AI. 3,103,693

HINGE MECHANISM Original Filed Aug. 21. 1956 2 Sheets-Sheet 1 IN V EN TOR. HOWA R0 J. T ENNIS WOOD L OWE L L W DUNBAR ATTORNEYS Sept. 17, 1963 H. J. TENNISWOOD ETAL 3,103,693

HINGE MECHANISM Original Filed Aug. 21, 1956 2 Sheets-Sheet 2 IN VEN TOR.

HOWARD J. TENN/SWOOD LOWELL M. DUNE/1R ATTORNEYS United States Patent Office Patented Sept. 17, 1963 3,103,693 HINGE MECHANISM Howard J. Tenniswo'od, Adrian, and L'owell W. Dunbar, Britton, Mich., assignors to Revco Inc., Deerfield, Mich., a corporation of Michigan Continuation of application Ser. No. 605,362, Aug. 21, 1956. This application Apr. 27, 1960, Ser. No. 25,012 8 Claims. (Cl. 16-190) This invention relates to hinges which more or less counterbalance the weights of doors or covers that swing about horizontal axes and is a continuation of our application Serial No. 605,362, for Hinge Mechanism, which was filed August 2.1, 1956, and now forfeited.

Such hinges usually are equipped with springs which are so stressed as to exert their maximum counter-balancing force when the doors or covers which are pivoted by means of the hinges are horizontal, the counterbalancing force diminishing gradually as the doors or covers are raised toward vertical position.

When door hinged upon horizontal axes are heavy, as they are in top opening freezers and refrigerators, the effort required to lift them if not at least partially counterbalanced might be so great as to tax the strength of a woman or child. When such doors are at or near vertical position they are easily swung on their hinges and the counterbalancing effect of the springs need to be only sufficient to keep the doors or covers from falling forwardly.

A counterbalancing spring usually is arranged therefore to be stressed more when the heavy door is horizontal than when it is in any other position, though it may be so connected to the hinge element that the effect of the force exerted by the spring dimishes gradually at a ratio that is different from the rate at which the elfort required to lift the door diminishes. Where a closed door is nearly completely counterbalanced (or over balanced) it is practically necessary to provide a latch or other means to hold the door shut. A latch or other holding means is particularly necessary where the door closes against a compressible gasket or other seal.

Children sometimes get into freezers, refrigerators or other cabinets through which there is little or no ventilation and are trapped therein by covers or doors that are automatically latched when they close. Even in cases Where latches are accessible from the inside a child may suffocate if it is unable to find or manipulate the latch.

It is important therefore that doors to refrigerators, freezers and the like be so hung that they can be easily pushed open from the inside and that they will not reclose after they are pushed open a short distance. Laws have been enacted in some jurisdictions which specify the maximum push required to open a door of a refrigerator or freezer or other unventilated box or cabinet (e.g. -15 lb. at the center of a door). It is import-ant also that the doors to refrigerators and freezers be held shut with sufficient force to make substantially airtight contact with a gasket or other sea'l. Attainment of these two divergent desiderata in .a simple hinge structure is a general object of this invention.

A more specific object of this invention is to provide a hinge structure which when used to pivotally connect a door to a top opening refrigerator, freezer or other cabinet will so near-1y counterbalance the Weight of the door when the door is closed that the door can be pushed open by a slight force, such as would be naturally applied by a small child upon finding itself imprisoned, and which having been opened slightly can be opened further with even less force. g

Another object of the invention is to provide a hinge structure which when used to pivotally connect a door to a top opening refrigerator, freezer or other cabinet will so nearly counterbalancethe weight of the door when the door is closed that the door can be pushed open by force not exceeding that prescribed by law or regulation in the jurisdiction in which the refrigerator, freezer or other cabinet is installed and which having been opened slightly can be opened further by the application of even less force.

Another object is to provide a hinge for a door which swings about a horizontal axis and is substantially horizontal When closed, said hinge embodying means which when such door is closed nearly but not completely counterbalances the weight of the door and when such door is opened slightly snaps into condition to more completely counterbalance the weight of the door.

Another object of the invention is to provide means for nearly counterbalancing the weight of a door swingable about a horizontal axis which enablm such door to be opened by small force and which when such door has been opened slightly restrains it against reclosing by its own weight.

An ancillary object is to provide a hinge structure which is not liable to pinch fingers of children or curious adults who play with or handle the hinge.

Other objects and numerous advantages of the invention will become apparent upon perusal of the following description illustrated by the accompanying drawings in which:

FIG. I is an elevational view of the upper portion of a top opening freezer cabinehhaving a door whichis hinged to the cabinet by the device of his invention, the device being shown in the condition that it assumes when the door is closed;

FIG. I I is a similar View, the device of this invention being shown in the condition that it assumes with the door open, part of the door being broken away;

FIG. III is a side elevational view, on an enlarged scale of a hinge per se embodying this invention, the parts being shown in the condition that they assume when a door that is mounted by means of the hinge is closed; and

FIG, IV is a front elevational view showing the parts in the same condition as that in which they are shown in FIG. II'I.

These drawings and the following description are intended to illustrate a preferred embodiment of the invention but not to impose limitations upon its scope.

A hinge 1 embodying the instant invention is shown as applied to a top opening freezer cabinet 2 having a door 3 which is shown as closed in FIG. I and as opened in FIG. II. The hinge 1 comprises a trough-like element 4 which is articulated by means of a hinge pintle 5 with a U-shaped member 6. The U-shaped member 6 has a pair of ears 7 and 8 adapted to be secured by means of screws or other fasteners to the rear edge of the door 3 while the trough-like member 4 has a pair of flanges 9 andg10 adapted to be secured by screws or other fasteners to the back of the cabinet 2.

Extending across the lower end of the trough-like element 4 and riveted or welded .to the walls 11 and 12 thereof is a pin 13 which preferably has a groove 14 girdling its center to receive the hooked end 15 of a retractile helical spring 16.

The upper end of the spring 16 is provided with a hook or eyelet 17 which is received in a channel 18 that encircles a spool-like roller 19 that is mounted to roll fore and aft on a track constituted by rails 20 and 21 that are formed integrally upon the lower edges of the U-shaped element 6.

As the roller 19 rolls fore and aft along the track constituted by the rails 20' and 21 it moves toward and away from the hinge pintle 5. The geometry of therears 7 and 8, the flanges 9 and 10 and the rails 20 and 2-1 is such that when the ears 7 and 8 and the flanges 9 and 10 lie along the same plane the front ends of the rails and 21 which are closest to the hinge pintle 5 are nearer to the pin 13 than are the rear ends of the rails 20 and 21. Hence, when the ears 7 and 8 lie along the same vertical plane as the flanges =9 and 10, as they do when the hinge is applied to a top opening freezer or refrigerator in the manner illustrated in FIG. I and the door 3 is closed, the roller 19 is near the hinge pintle 5 where the lever arm upon which the spring 16 acts is of minimum length.

When the door 3 is closed the rails 20 and 21 are so nearly perpendicular to a plane passing through the axis of the pin 13 and the axis of the roller 19 located at the front end of the rails that opening the door 3 slightly causes the rails 20 and 21 to slope downwardly and rearwardly thus bringing the rear ends of the rails nearer to the pin 13 than are the front ends of the rails. Thereupon the tens-ion of the spring 16 snaps the roller to the rear ends of the rails and multiplies the length of the lever arm upon which the force of the spring acts to swing the door 3 in an opening direction.

The stilfness of the spring 16 and the weight of the door 3 can be so related that when the roller snaps to the rear ends of the rails 20 and 21 the door will be opened further. Alternatively, the door 3 may be so weighted in relation to the stiffness of the spring '16 that after the roller 19 has snapped to the rear ends of the rails the spring will merely hold the door against reclosing.

As will be apparent upon examination of FIGS. I, II and III the back of the trough element 4 is curved, as indicated by the reference numeral 22, about the axis of the hinge pintle 5, and the back edge of the sloping wall of the U-shaped member 6 lies within the trough-shaped member 4 in all positions of the door 3. As the door is opened and closed the back edge of the sloping wall of the U- shaped member 6 wipes closely along the curved portion of the back wall of the trough-shaped element 4 so that it is impossible while the edge is in reach for a person to insert a finger between the said edge and the said curved portion. placed upon the U-shaped member 6 it will merely ride upon the member as it swings in either direction and will not be squeezed between any part of the U-shaped member 6 and any part of the trough-shaped member 4.

In recapitulation of the invention, it comprises a counterbalancing hinge which is spring biased by a force which is altered by changing the length of the moment arm upon which the spring is effective at a predetermined relative position of the hinge elements. A hinge base 4 is pivotally connected by pintle 5 to a hinge wing 6 having m'de walls upon which are supported bearing surfaces 20 and 21. A retainer pin or rollers 19 are carried on and are movea-ble on the bear-ing surfaces between a first position and a second position more distantly spaced from the pintle than the first position. Spring 16 imposes a biasing force on the hinge wing, as toward the pin 13 in the lower portion of that base and is secured to the base at one effective end, as at pin =13 by hook l5, and to the retainer pin or rollers 19 at its other efiective end, as by the hook 19. The bearing surfaces 20 and 21 are oriented on the hinge wing 6 such that for a first position of that wing with respect to the base, when the door of a top opening cabinet employing the hinge is essentially closed, they are inclined with respect to the line along which the spring force between the hinge wing and hinge base is effective toward the hinge pintle and for a second position of the wing, when the door is opened slightly, they are inclined with respect to that line away from the hinge pintle. As a result of this inclination of the bear-ing surface and the freedom of the retainer pin or roller to move along this surface, the biasing force automatically shifts the pin on the surface from a position spaced from the pintle when the door is partially or fully opened to a position closer to the pintle when the door is moved to the closed position whereby the moment arm upon which the spring force is effective and It will be observed further that if a finger is 4 Cir 4 thus the spring loading of the hinge is substantially decreased when the door is moved to the closed position from that imposed when it is partially or fully open.

It is to be understood that the device described in the foregoing specification and illustrated in the accompanying drawings is exemplary only and that it is subject to modification and change within the spirit and scope of the subjoined claims.

Having described the invention, we claim:

1. In a device for hinging a door on a horizontal axis to a top opening cabinet, in combination, an upper hinge element having parallel sides, a sloping top connecting said parallel sides, ears extending outwardly from said parallel sides and adapted to be secured to the vertical rear edge of a door, rails extending along said parallel sides, a trough-like hinge element, a pintle pivoting said upper hinge elements to said trough-like hinge element, flanges extending outwardly from said trough-like binge element and adapted to be secured to the vertical rear side of a cabinet, a retractile spring, an anchor for said retractile spring adjacent the lower end of said trough-like element, a roller rollable upon said rails, the upper end of said retractile spring being connected to said roller, said rails having a first limit of travel for said roller adjacent said pintle, a second limit of travel for said roller more remote from said pintle than said first limit and being disposed horizontally when the door is closed, the direction of pull of said spring being such that said roller is automatically located at said first limit when said door is closed and is automatically moved away from said pintle to said second limit when said rails are tilted downwardly upon slight opening of the door, said spring bemg distorted essentially the maximum amount to impose an essentially maximum force on said roller and said roller being at said first limit to provide a relatively short mo ment arm about said pintle to generate a moment opposing and less than the gravity moment of the door about said pintle when the door is fully closed, said spring being distorted essentially said maximum to impose on said roller a force of the same magnitude as said essentially maximum force and said roller being at said second limit to provide a relatively long moment arm about said pintle to generate a maximum moment opposing and fully counterbalancing the gravity moment of the door when the door is open to a position displaced slightly from fully closed, and said roller while at said second limit progressively moving the line along which said spring force is imposed toward said pintle to progressively reduce the moment arm about said pintle and said spring distortion being progressively reduced to progressively reduce the moment about said pintle opposing the gravity moment of the door while maintaining said gravity moment fully counterbalanced when said door is displaced in an opening direction from said slightly open position. 2. In a device for hinging a door on a horizontal axis to a top opening cabinet, in combination, an upper hinge element adapted to be secured to the vertical rear edge of a door, a lower hinge element, articulating means connecting said upper hinge element to said lower hinge element, said lower hinge element being adapted to be secured to the vertical rear side of a cabinet, a retractile spring, an anchor for said retractile spring adjacent the lower end of said lower hinge element, a substantially horizontal track on said upper hinge member, a roller rollable upon said track, the upper end of said retractile spring being connected to said roller, said track having a first limit of travel for said roller adjacent said articulating means and a second limit of travel for said roller more remote from said articulating means than said first limit, said elements, said track and said articulating means being so disposed and the direction of pull of said spring being such that said roller is automatically located at said first limit near said articulating means when said door is closed, and being such that said roller is automatically snapped away from said articulating means to said second limit when said door is opened slightly, said spring being distorted essentially a maximum amount to impose an essentially maximum force on said roller and said roller being at said first limit to provide a relatively short moment arm about said articulating means to generate a moment opposing and less than the gravity moment of the door when the door is fully closed, said spring being distorted essentially to said maximum to impose a force of the same magnitude as said essentially maximum rtorce on said roller and said roller being at said second limit to provide a relatively long moment arm about said articulating means to generate a maximrmr moment opposing and fully oounterbalancing the gravity moment of the door when the door is opened to a position displaced slightly from fully closed, and said roller while at said second limit progressively moving the line along which said spring force is imposed toward said articulating means to progressively reduce the moment arm about said articulating means and said spring distortion being progressively reduced to progressively reduce the moment about said articulating means opposing the gravity moment of the door While maintaining said gravity moment fully counterbalanced when said door is displaced in an opening direction from said slightly opened position.

3. In a device for hinging a door on a horizontal axis to a top opening cabinet in combination, an upper binge element adapted to be fixed to an edge of said door, a lower hinge element adapted to be fixed to said cabinet, a horizontal pivotal connection between said upper and lower hinge elements, said upper hinge element having spaced sides extending outwardly from said edge of the door and substantially perpendicular to said pivotal connection, and means for biasing said door toward an open position by imposing a fonce along a line of action lying outwardly of said pivotal connection for all positions of said door and directed to create a moment about said pivotal connection opposing the gravity moment of said door about said pivotal connection, said means including an elongated substantially linear bearing surface on each of said sides of said upper hinge element having a first stop at one end thereof spaced a given distance from said pivotal connection and a second stop on the other end spaced from said pivotal connection a distance substantially greater than said given distance, said bearing surfaces being in transverse alignment, a bearing member supported on each of said bearing surfaces, an elastic member connected to said bearing member, and a connection from said elastic member to said lower hinge element, said bearing surfaces being oriented on and moving with said upper hinge element as said door is moved between an opened and closed position so that the biasing force on said bearing member has a component along said surfaces toward said first stop to shift said bearing member to said first stop when said door substantially is closed and a component along said surfaces toward said second stop to shift said bearing member to said second stop when said door is displaced slightly toward the opened position from the closed position to augment the balancing efiect of said elastic member upon said door, said elastic member being distorted essentially a maximum amount to impose an essentially maximum force on said bearing member and said bearing member being at said first stop to provide a relatively short moment arm about said pivotal connection to generate a moment opposing and less than the gravity moment of the door when the door is fully closed, said elastic member being distorted essentially said maximum to impose a force essentially equal to said maximum force on said bearing member and said bearing member being at said second stop to provide a relatively long moment arm about said pivotal connection to generate a maximum moment opposing and fully oounterbalancing the gravity moment of the door when the door is open to a position displaced slightly from said fully closed position, and said bearing member while at said second stop progressively moving the line along which said biasing force is imposed toward said pivotal connection to progressively reduce the moment arm about said pivotal connection and said elastic member distention being progressively reduced to progressively reduce the mement about said pivotal connection opposing the gravity moment of the door while maintaining said gravity moment fully counterbalanced when said door is displaced in an opening direction from said slightly opened position.

4. In a device for hinging a door on a horizontal axis to a top opening cabinet, in combination, an upper binge element having parallel sides, a top connecting said parallel sides, mounting means for securing said upper binge element to the vertical rear edge of a door, rails extending along said parallel sides, a trough-like hinge element, la pintle pivoting said upper hinge element to said troughlilce hinge element, mounting means for securing said trough-like hinge element to the vertical rear side of a cabinet, a biasing spring, an anchor for said spring within said trough-like element, a roller rollable upon said rails, said rails having a first limit of travel for said roller adjacent said pintle and a second limit of travel [for said roller more remote from said pintle than said first limit, means connecting said spring to said roller, said rails being disposed substantially horizontally when the door is closed and the direction of force of said spring being such that said roller is automatically located at said first limit near said pintle, and being inclined to the direction of force through said connection upon slight opening of the door whereby said roller is automatically moved away from said pintle, said spring being distorted essentially the maximum amount to impose an essentially maximumforce on said roller and said roller being at said first limit to provide a relatively short moment arm about said pintle to generate a moment opposing and less than the gravity moment of the door about said pintle when the door is fully closed, said spring being distorted essentially said maximum to impose on said roller a force of the same magnitude as said essentially maximum force and said roller being at said second limit to provide a relatively long moment arm about said pintle to generate a maximum moment opposing and fully counter-balancing the gravity moment of the door when the door is open to a position displaced slightly from fully closed, and said roller while at said second limit progressively moving the line along which said spring force is imposed toward said pintle to progressively reduce the moment arm about said pintle and said spring distortion being progressively reduced to progressively reduce the moment about said pintle opposing the gravity moment of the door While maintaining said gravity moment fully counterbalanced when said door is displaced in an opening direction from said slightly open position.

5. 'In a device for hin'ging a door on a horizontal axis to a top opening cabinet, in combination, an upper hinge element adapted to be secured to the vertical rear edge of a door, a lower hinge element, articulating means connecting said upper hinge element to said lower hinge element, said lower hinge element being adapted to be seicured to the vertical rear side of a cabinet, a biasing spring, an anchor for one eiiective end of said spring secured to said lower binge element, a substantially horizontal track on said upper hinge member, a roller roll-able upon said track, said track having a first limit of travel for said roller adjacent said anticulating means and a second limit of travel tfior said roller more remote from said articulating means than said first limit, a connection from a second efiective end of said spring to said roller, said elements, said track and said articulating means being so disposed and the biasing direction of said spring being such that said roller is automatically locatedtat said first limit near said articulating means when said door is closed, and being such that said roller is automatically snapped away from said articulating means to said second limit when said door is opened slightly, said spring being distorted essentially a maximum amount to impose an essentially maximum force on said roller and said roller being at said first limit to provide a relatively short moment arm about said articulating means to generate a moment opposing and less than the gravity moment of the door when the door is fully closed, said spring being distorted essentially to said maximum to impose a force of the same magnitude as said essentially maximum force on said roller and said roller being at said second limit to provide a relatively long moment arm about said articulating means to generate a maximum moment oposing and fully counterbalancing the gravity moment of the door when the door is opened to a position displaced slightly from fully closed, and said roller while at said second limit progressively moving the line along which said spring force is imposed toward said articulating means to progressively reduce the moment arm about said articulating means and said spring distortion being progressively reduced to progressively reduce the moment about said articulating means opposing the gravity moment of the door while maintaining said gravity moment fully counterbalanced when said door is displaced in an opening direction from said slightly opened position.

6. A spring-loaded hinge assembly for pivotally mounting about a horizontal axis a relatively heavy lid upon the container of a refrigerator cabinet, retaining the lid whereby a portion of the lid weight eifects sealing contact between the lid and the container when the lid is in closed position and counterbalancing the weight of said lid in partially or fully open position, comprising a hinge base affixed to the rear of the container, a hinge wing afiixed to the lid and provided with spaced side walls pivotally connected to the upper end of the hinge base, an elongated bearing surface supported on each of the side walls of said hinge wing with said bearing surfaces provided in alignment, a retainer pin bridging said side walls of the hinge wing with the ends thereof carried and movable on said aligned bearing surfaces, and a spring in said hinge base with one effective end secured thereto, said bearing surfaces having a first limit of travel for said pin adjacent the pivotal connection and a second limit of travel for said pin more remote from said pivotal connection than said first limit, a connector from said spring engaging the retainer pin, said bearing surface being inclined with respect to the line along which the spring force between said hinge wing and said hinge base is effective toward the pivotal connection when the lid is closed and away therefrom when the lid is opened, said pin being shiftable on said bearing surfaces from said first limit when the lid is closed to said second limit when the lid is opened, said spring being distorted essentially the maximum amount to impose an essentially maximum force on said retainer pin and said retainer pin being at said first limit to provide a relatively short moment arm about said pivotal connection to generate a moment opposing and less than the gravity moment of the lid about said pivotal connection when the lid is fully closed, said spring being distorted essentially said maximum to impose on said retainer pin a force of the same magnitude as said essentially maximum force and said retainer pin being at said second limit to provide a relatively long moment arm about said pivotal connection to generate a maximum moment opposing and fully counter-balancing the gravity moment of the lid when the lid is open to a position displaced slightly from fully closed, and said retainer pin while at said second limit progressively moving the line along which said spring force is imposed toward said pivotal connection to progressively reduce the moment arm about said pivotal connection and said spring distortion being progressively reduced to progressively reduce the moment about said pivotal connection opposing the gravity moment of the lid while maintaining said gravity moment fully counterbalanced when said lid is displaced in an opening direction from said slightly open position.

7. In a refrigerator having a container open at the top and a relatively heavy and pivotally mounted lid providing an air-tight closure for said container when the lid is lowered to closed position, a hinge assembly comprising a hinge base mounted upon the container at the rear thereof and a hinge Wing mounted upon the lid at the rear thereof, a spring, means connecting a first portion of said spring to said hinge base, said hinge wing having spaced side Walls, a hinge pin for pivotally connecting the hinge wing and hinge base and pivotally mounting the lid upon the container, an elongated bearing surface on each of said side walls spaced from said hinge pin, and a retainer pin carried on and shiftable along said aligned bearing surfaces with a second portion of said spring spaced from said first portion attached to said retainer pin, said bearing surfaces having a first limit of travel for said retainer pin adjacent said hinge pin and a second limit of travel for said retainer pin more remote from said hinge pin than said first limit, said bearing surfaces being arranged in aligned relation and inclined with respect to the biasing direction of the spring force etween said hinge base and hinge wing toward the hinge pin when the lid is closed and being inclined away from said hinge pin when the lid is opened, Whereby said retainer pin is moved to said second limit on said hearing surfaces with said spring balancing the weight of said lid in its partially or fully open positions, whereby the moment arm from said hinge pin to the line along which said spring force is imposed on said retainer pin and through said second limit diminishes as the lid is moved from its partially opened to its fully opened position, and whereby said retainer pin is moved to said first limit on said bearing surfaces and toward said hinge pin when the lid is moved to the closed position in which the balancing effect of said spring is decreased and a portion of the weight of the lid is effective to seal the lid upon the container.

8. In a refrigerator having a container open at the top, a relatively heavy lid providing a closure for said contniner and a compressive gasket between said container and said lid to provide a substantially air-tight seal therebetween when said lid is lowered to closed position, a hinge assembly for retaining the lid counterbalance when in partially or fully opened position and retaining the lid whereby a portion of the lid weight compresses said gasket when in closed position to effect a seal between the lid and the container comprising first and second hinge elements, means for pivotally connecting said first and second hinge elements, means securing one of said first and second hinge elements to said container at the rear thereof, means to secure the other of said first and second hinge elements to said lid at the rear thereof, a biasing spring in said second hinge element having one effective end coupled to said first hinge element and the other effective end coupled to said second hinge element to impose a moment about said pivotal connection to oppose the gravity moment of said lid, said first hinge element having spaced side walls each provided with an elongated bearing surface spaced from said pivotal connection with the bearing surfaces arranged in aligned relation and inclined with respect to the biasing direction of the spring force between said hinge elements toward the pivotal connection when the lid is closed and in the opposite direction when the lid is opened slightly from the closed position, and a retainer pin carried on and shiftable along said aligned bearing surfaces with one end of said spring attached to said retainer pin to provide the spring coupling to said first hinge element, said retainer pin being shiftable on said bearing surfaces to a first position adjacent said pivotal connection and said spring being distorted essentially a maximum when said lid is in the fully closed position to impose essentially maxinum spring force on a moment arm about said pivotal connection and generate a moment less than the opposing gravity moment of said door whereby said gravity moment imposes a sealing compressive force on said 9 g-askeLsaid retainer pin being shifted on said bearing surfaces to a second position more remote from said pivotal connection than said first position to increase the separation from said pivotal connection of the line along which said spring force acts and said spring being distorted essentially to said maximum when said lid is opened slightly from said fully closed position to impose a spring moment around said pivotal connection fully counterbalancing said gravity moment of said lid, said retainer pin While in said second position progressively reducing said moment arm around said pivotal connection upon which said spring force acts as said door is progressively displaced from said slightly opened position in an opening direction.

5 References Cited in the file of this patent UNITED STATES PATENTS 2,149,114 Constantine Feb. 28, 1939 2,316,302 Van Dyk et a1. Apr. 13, 1943 2,584,372 Swedman Feb. 5, 1952 10 2,691,934 Erwin Oct. 19, 1954 

1. IN A DEVICE FOR HINGING A DOOR ON A HORIZONTAL AXIS TO A TOP OPENING CABINET, IN COMBINATION, AN UPPER HINGE ELEMENT HAVING PARALLEL SIDES, A SLOPING TOP CONNECTING SAID PARALLEL SIDES, EARS EXTENDING OUTWARDLY FROM SAID PARALLEL SIDES AND ADAPTED TO BE SECURED TO THE VERTICAL REAR EDGE OF A DOOR, RAILS EXTENDING ALONG SAID PARALLEL SIDES, A TROUGH-LIKE HINGE ELEMENT, A PINTLE PIVOTING SAID UPPER HINGE ELEMENTS TO SAID TROUGH-LIKE HINGE ELEMENT FLANGES EXTENDING OUTWARDLY FROM SAID TROUGH-LIKE HINGE ELEMENT AND ADAPTED TO BE SECURED TO THE VERTICAL REAR SIDE OF A CABINET, A RETRACTILE SPRING, AN ANCHOR FOR SAID RETRACTILE SPRING ADJACENT THE LOWER END OF SAID TROUGH-LIKE ELEMENT, A ROLLER ROLLABLE UPON SAID RAILS, THE UPPER END OF SAID RETRACTILE SPRING BEING CONNECTED TO SAID ROLLER, SAID RAILS HAVING A FIRST LIMIT OF TRAVEL FOR SAID ROLLER ADJACENT SAID PINTLE, A SECOND LIMIT OF TRAVEL FOR SAID ROLLER MORE REMOTE FROM SAID PINTLE THAN SAID FIRST LIMIT AND BEING DISPOSED HORIZONTALLY WHEN THE DOOR IS CLOSED, THE DIRECTION OF PULL OF SAID SPRING BEING SUCH THAT SAID ROLLER IS AUTOMATICALLY LOCATED AT SAID FIRST LIMIT WHEN SAID DOOR IS CLOSED AND IS AUTOMATICALLY MOVED AWAY FROM SAID PINTLE TO SAID SECOND LIMIT WHEN SAID RAILS ARE TILTED DOWNWARDLY UPON SLIGHT OPENING OF THE DOOR, SAID SPRING BEING DISTORTED ESSENTIALLY THE MAXIMUM AMOUNT TO IMPOSE AN ESSENTIALLY MAXIMUM FORCE ON SAID ROLLER AND SAID ROLLER BEING AT SAID FIRST LIMIT TO PROVIDE A RELATIVELY SHORT MOMENT ARM ABOUT SAID PINTLE TO GENERATE A MOMENT OPPOSING AND LESS THAN THE GRAVITY MOMENT OF THE DOOR ABOUT SAID PINTLE WHEN THE DOOR IS FULLY CLOSED, SAID SPRING BEING DISTORTED ESSENTIALLY SAID MAXIMUM TO IMPOSE ON SAID ROLLER A FORCE OF THE SAME MAGNITUDE AS SAID ESSENTIALLY MAXIMUM FORCE AND SAID ROLLER BEING AT SAID SECOND LIMIT TO PROVIDE A RELATIVELY LONG MOMENT ARM ABOUT SAID PINTLE TO GENERATE A MAXIMUM MOMENT OPPOSING AND FULLY COUNTERBALANCING THE GRAVITY MOMENT OF THE DOOR WHEN THE DOOR IS OPEN TO A POSITION DISPLACED SLIGHTLY FROM FULLY CLOSED, AND SAID ROLLER WHILE AT SAID SECOND LIMIT PROGRESSIVELY MOVING THE LINE ALONG WHICH SAID SPRING FORCE IS IMPOSED TOWARD SAID PINTLE TO PROGRESSIVELY REDUCE THE MOMENT ARM ABOUT SAID PINTLE AND SAID SPRING DISTORTION BEING PROGRESSIVELY REDUCED TO PROGRESSIVELY REDUCE THE MOMENT ABOUT SAID PINTLE OPPOSING THE GRAVITY MOMENT OF THE DOOR WHILE MAINTAINING SAID GRAVITY MOMENT FULLY COUNTERBALANCED WHEN SAID DOOR IS DISPLACED IN AN OPENING DIRECTION FROM SAID SLIGHTLY OPEN POSITION. 